FIGS. 1 and 2 schematically illustrate a conventional die package 10. This package 10 includes a semiconductor die 20 that is attached to a front surface 52 of a substrate 50 by a die attach paste 40. The die attach paste 40 is typically applied in a plastic or flowable state and the die 20 is pressed onto the paste, causing excess paste 40 to bleed out from underneath the die 20. A plurality of bonding wires 70 electrically connect contacts 24 carried by the die 20 to bond pads 54 carried by the upper surface 52 of the substrate 50. The bond pads 54 of the substrate 50 are connected to ball bond pads 58 on the back surface 56 of the substrate 50 by vias 60. These ball bond pads 58 may be used, for example, to carry solder balls to electrically connect the package 10 to another microelectronic component. An encapsulant 80 (shown in phantom and FIG. 1) covers the top and sides 28 of the die 20.
Generally, the bond pads 54 of the substrate 50 must be spaced a sufficient distance d to minimize the chance that the die attach paste 40 will bleed out far enough to cover the bond-pad 54. To accommodate the size of the bond pads 54, the periphery 62 of the substrate 50 is spaced at least a minimum distance D from the periphery 28 of the die 20. As suggested in FIG. 1, the lateral dimensions of the encapsulant 80 are typically about the same as those of the substrate 50, such that the periphery 82 of the encapsulant 80 is generally flush with the periphery 62 of the substrate 50. Typical dimensions for the minimum distance D are at least about one millimeter. At least one conventional package 10 achieves a minimum distance D of about 0.8 millimeters by dicing the packages with the saw blade cutting the width of the bond pads 54. Since the periphery 62 is spaced the minimum distance D from each side of the rectangular die 20, such a conventional package 10 is about 1.6 millimeters wider than the die 20 of the package 10.
Market pressures to reduce the size of electronic devices, e.g., mobile telephones and hand-held computing devices, place a premium on the space or “real estate” available for mounting microelectronic components on a printed circuitboard or the like. Similar density pressures also impact manufacturers of computers and other larger-scale electronic devices. An extra 2.5 millimeters per package 10, for example, can significantly add to the dimensions of an array of packaged memory chips, for example.